Water filtration has become common in homes, offices and other places to produce cleaner and better tasting water. Accordingly, water containers such as pitchers have been equipped with filtration systems. In some instances, these filtration systems may employ a filter core to which one end of a piece of a filter medium is attached, such as by gluing. The free end of the piece of filter medium is then wrapped around the filter core and secured in place with more glue. The filter core includes various openings that allow unfiltered water to enter the interior of the filter core by passing through the filter medium. As well, the fluid in the filter core may also exit the filter core by passing through the filter medium. Thus, the filter core and filter medium configuration may enable a dual pass—dual filtration process.
The use of a filter core with attached filter medium has proven problematic in some respects however. For example, the filter medium is often attached to the filter core in such a way that a vertical seam is defined at the location where the two ends of the piece of filter medium butt against each other. Typically, the seam is characterized by gaps and/or other imperfections that enable fluid to enter and exit the filter core without passing through the filter medium. This condition is sometimes referred to as bypass, since the unfiltered fluid bypasses the filter medium. Bypass is a concern at least because it compromises the overall effectiveness of the filter. Correspondingly, bypass may also have a negative influence on consumer perception of the effectiveness of the filter.
Another concern with structures such as those described above relates to the methods used to attach the filter medium to the filter core. In particular, some filter products are manufactured by using glue to attach the filter medium to the filter core. The use of glue may complicate the manufacturing process. As well, the use of glue may not be viewed favorably by consumers.
Finally, some filter products require the use of O-rings, clamps and/or other mechanical devices in an attempt to prevent fluid from entering or exiting the filter core at the boundaries of the filter medium. However, the use of mechanical devices such as O-rings and clamps in this way increases the cost and complexity of the design, and may not contribute significantly to avoiding or reducing the bypass problem. Moreover, contact with devices such as O-rings can damage some types of filter media.
In light of problems such as those noted above, it would be useful to provide a filter assembly including a filter medium that is configured and arranged to reduce, or eliminate, bypass problems typically associated with a filter medium that defines a vertical seam when attached to a filter core. As well, it would be useful to provide a filter assembly that can be reliably constructed without the use of glue to attach the filter medium to the filter core. It would also be useful to provide a filter assembly that can be configured without the use of O-rings or other mechanical devices to seal the upper and lower edges of the filter medium so as to avoid or minimize bypass at those locations. Finally, it would be useful to provide a filter assembly that can provide dual, or more, filtration in a single pass of fluid through the filter medium.